A Novel Complex Filter Design With Dual Feedback for High Frequency Wireless Receiver Applications

• Published in: IEEE transactions on circuits and systems. II, Express briefs Express briefs, 2021-06, Vol.68 (6), p.1748-1752
• Main Authors: Veerendranath, P. S., Sharma, Vivek, Vasantha, M. H., Kumar, Y. B. Nithin
• Format: Article
• Language: English
• Subjects: <italic xmlns:ali="http://www.niso.org/schemas/ali/1.0/" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">Gₘ -C; Bandwidth; Bandwidths; Circuit design; Circuit stability; CMOS; complex filter; Design; Filter design (mathematics); Frequency shift; image rejection ratio (IRR); Low power; low voltage; LTE; Negative feedback; positive feedback compensation; Power consumption; Receivers; Rejection; Test vehicles; Transconductance; Transistors; Voltage gain; Wireless communication
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2020.3031658

This brief presents a low-power tunable G_{m}-C complex filter for wireless receiver applications. The proposed design achieves an unconditional stability thanks to the internal negative feedback mechanism. This negative feedback helps in achieving a high-frequency shift and the negative transconductance of the circuit improves the Image Rejection Ratio (IRR) and Common Mode Rejection Ratio (CMRR) of the proposed design. The proposed circuit has independent control over bandwidth and frequency shift which makes an attractive solution for multi-standard and multi-mode wireless receiver applications. A second order complex filter is designed for Long Term Evolution (LTE) application and used as a test vehicle to verify the proposed concept. The circuit is designed using a 180 nm CMOS process with a power consumption of 106~\mu \text{W} from a 1 V supply voltage. It is centered at 9.2 MHz with −3 dB bandwidth of 1.4 MHz and provides an IRR of 51 dB with a voltage gain of 45 dB. The total integrated in-band Input Referred Noise (IRN) is 70~\mu V_{rms} and FoM of 47 aJ is achieved. The area of the layout of the proposed design is 78~\mu \text{m} X 78~\mu \text{m} .